1. Field of the Invention
The present invention relates to a pneumatic tire improved in steering stability and noise performance while maintaining the drainage performance.
2. Description of the Related Art
A pneumatic tire having a tread portion provided with circumferentially extending main grooves is proposed. Such main grooves may drain the water between the tread portion and the road. Also, the larger the groove width of the main groove, the better the drainage performance is.
However, when the groove width of the main groove is too large, the noise performance is liable to deteriorate due to the air tube resonance therein. Moreover, when the tread portion has a small land ratio, the steering stability of the tire is liable to decrease due to the small rigidity of the tread portion.
JP-2003-285610-A1 discloses a pneumatic tire having a tread portion provided with a plurality of main grooves to form a rib-tread pattern. The tire above has a limited total groove width in a certain range for main grooves, and is neither provided any sipes nor slots which extend from the main grooves to increase the rigidity of ribs. The tire may improve the steering stability and noise performance. However, such a tire has an unsatisfactory drainage performance.